Wouldn't it be Lumia 9xx? And, is it the manufacturer or the carrier that name the phones?

I would imagine it follows Nokia's branding.
If the branding is anything else than Lumia 9xx it would mean the name comes from verizon.

That said i would also imagine that Nokia would demand that the Lumia name must be there. Nokia's whole backbone is about the Lumia brand inside Windows Phone. Bringing their own ecosystem inside another ecosystem.